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Recent Progress
Construction for stage 3A (the flyover ramp) is in progress.
The Deviations and Channelization Plans for stage 3B were approved in July, and the Design Decision Package is being reviewed. Revisions are also being made to stormwater design to comply with new City of Redmond codes and the draft Stormwater Report has been reviewed by our Hydraulics staff. This will feed into the completion of the Biological Assessment (BA) for stage 3B of the project which is scheduled to be complete in late October.
A Design Workshop was held on July 31, 2007, with the City of Redmond and permitting agencies to discuss the stormwater design for the project and to develop a plan to move forward. Prior to the workshop, general agreement was reached with the City on floodplain storage and stormwater treatment requirements. The project will provide compensatory floodplain storage for Bear Creek within the project area right of way, and will also provide enhanced stormwater treatment within the roadway prism using the Ecology Embankment BMP followed by sheet flow dispersion through the Bear Creek buffer. This will allow the deletion of a detention vault for flow control. We are still working with the City to resolve the issue of buffer impacts to Bear Creek. WSDOT is proposing to mitigate for the permanent stream buffer impacts at an off-site location within the Bear Creek Basin and to enhance the functions of the remaining buffer within the project limits.
At the June QPR, we reported that the results of the Cost Risk Assessment performed earlier that month indicated the project was approximately $6 million over budget. Since that time, we have looked at ways to reduce the project cost and have identified a number of potential cost savings. The biggest reduction is the deletion of the detention vault at a savings of $3.7 million. In addition, the new bridges being constructed for the on and off ramps at the West Lake Sammamish Parkway Interchange have been modified to a prestressed concrete girder design. This will result in a savings of approximately $1 million, and revisions to the retaining wall design have provided another $1 million in savings.
Based on the revised estimate using the cost savings listed above, the project is currently within budget. However, we are still negotiating with the City of Redmond on the stream buffer issue. There is a risk that the Advertisement date may be delayed by as much as a year if the City Council does not approve the proposed buffer mitigation and issue a Shoreline Permit. This will result in additional inflation costs. We recommend that the project be placed on the watch list for the December QPR, and we will continue to monitor the costs as the PS&E is developed.
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